| 摘要 |
A method for preparing 1,5-dimethylnaphthalene from 5-ortho-tolyl-pentene is provided to improve selectivity and production yield by the re-cyclization of unreacted materials. 1,5-Dimethylnaphthalene is prepared by the alkenylation(S11), cyclization(S12) and dehydrogenation(S13) of 5-ortho-tolyl-pentene, wherein the unreacted 5-ortho-tolyl-pentene obtained by fractional distillation(S14) after the dehydrogenation is mixed with 5-ortho-tolyl-pentene generated after the alkenylation for re-cyclization(S22). Preferably the re-cyclization is carried out at a temperature of 140 deg.C and at a pressure of 1 atm in the presence of a zeolite beta catalyst having a SiO2/Al2O3 molar ratio of 5.0-300.
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